PRE-COLLISION SYSTEM SYSTEM DESCRIPTION


  1. PRE-COLLISION SYSTEM DESCRIPTION


    1. The pre-collision system determines the possibility of a collision according to information such as the position of the obstacle and its relative speed, and provides optimal control to avoid the collision and control to reduce the impact during the collision via warnings, brake assist and automatic braking.

  2. FUNCTION OF COMPONENTS

    Component Function
    Pre-collision City Sensor

    • Acquires information about the preceding vehicle from a monocular camera sensor and laser sensor to perform pre-collision system control.

    • Sends the information display, PCS warning light and PCS warning message signal to the combination meter assembly based on pre-collision control information.

    • Sounds the pre-collision city buzzer based on pre-collision control information.
    Pre-collision System Cancel Switch Assembly Turns the pre-collision system on/off and changes the warning timing.
    Pre-collision City Buzzer Sounds according to signals from the pre-collision city sensor.
    Combination Meter Assembly

    • Displays the pre-collision system control status (ON/OFF) and warning timing.

    • During a system malfunction, warns the driver by displaying a message in the multi-information display according to the nature of the problem in the system, blinking the PCS warning light and master warning light and sounding the meter buzzer.
    ECM

    • Detects the shift position signal and accelerator opening angle and sends that information to the pre-collision city sensor.

    • Performs engine output control based on information from the pre-collision city sensor.
    Skid Control ECU (Brake Actuator Assembly)

    • Sends information such as the vehicle speed signal, stop light switch signal and brake control hydraulic pressure to the pre-collision city sensor.

    • Performs brake hydraulic pressure and emergency brake signal control based on information from the pre-collision city sensor.
    Steering Angle Sensor (Spiral with Sensor Cable Sub-assembly) Detects the steering angle and steering direction.
    Yaw Rate Sensor Detects the yaw rate and acceleration of the vehicle and transmits signals to the pre-collision city sensor.
    Main Body ECU (Instrument Panel Junction Block Assembly) Sends destination information to the pre-collision city sensor.
    VSC OFF Switch Disables the pre-collision brake and pre-collision brake assist operation when the switch is turned on.

  3. OUTLINE OF PRE-COLLISION DETECTION


    1. Collision detection


      1. The system determines in advance the possibility of a collision and whether the collision can be avoided based on road surface conditions and the position and speed of the preceding vehicle according to information about the preceding vehicle from the pre-collision city sensor.

        Tech Tips

        For details about the system, see "Outline of Pre-collision System Control" and the function descriptions.

    2. Component

      Component Detection Content
      Pre-collision city sensor Obstacle in front (vehicle)

  4. OUTLINE OF PRE-COLLISION SYSTEM CONTROL

    Control Condition Start of Control Sender ECU Receiver ECU Operated Parts
    Pre-collision warning Collision is possible Pre-collision city sensor Combination meter assembly

    • Combination meter assembly (warning display)

    • Pre-collision city buzzer (warning sound)
    Pre-collision brake assist Collision is highly possible Pre-collision city sensor

    • Combination meter assembly

    • Skid control ECU (brake actuator assembly)

    • Combination meter assembly (warning display)

    • Pre-collision city buzzer (warning sound)

    • Brake actuator assembly
    Pre-collision brake Possibility of a collision is very high Pre-collision city sensor

    • Combination meter assembly

    • Skid control ECU (brake actuator assembly)

    • ECM

    • Combination meter assembly (warning display)

    • Pre-collision city buzzer (warning sound)

    • Brake actuator assembly

  5. PRE-COLLISION ALARM CONTROL


    1. When the system determines that the possibility of a frontal collision with a vehicle is high, a buzzer will sound and warning message will be displayed on the multi-information display to urge the driver to take evasive action.

  6. PRE-COLLISION BRAKE ASSIST CONTROL


    1. When the system determines that the possibility of a frontal collision with a vehicle is high, the system applies greater braking force in relation to how strongly the brake pedal is depressed.

  7. PRE-COLLISION BRAKE CONTROL


    1. When the system determines that the possibility of a frontal collision with a vehicle is high, the system warns the driver. If the system determines that the possibility of a collision is extremely high, the brakes are automatically applied to help avoid the collision or reduce the collision speed.

      Note

      When the system detects that the driver is attempting to cancel operation of the system by performing operations such as the following, pre-collision brake control will be canceled.


      • The accelerator pedal is depressed strongly.

      • The steering wheel is operated quickly.

  8. VSC OFF SWITCH


    1. Turning the VSC OFF switch on disables pre-collision brake assist control and pre-collision brake control.

      Tech Tips

      When the VSC OFF switch is held for 3 seconds or more, the mode changes to VSC OFF mode, the PCS warning light illuminates and "VSC TURNED OFF PRE-COLLISION BRAKE SYSTEM UNAVAILABLE" is displayed on the multi-information display.

  9. PRE-COLLISION SYSTEM (PCS) OPERATION CONDITIONS


    1. Shared conditions:


      • Pre-collision system is ON

      • Shift lever is not in R

      • PCS warning light in combination meter assembly does not blink

    2. Pre-collision warning operation conditions:


      • Vehicle speed is approximately 15 km/h (10 mph) or more and approximately 140 km/h (87 mph) or less

      • Relative speed of vehicle ahead is approximately 15 km/h (10 mph) or more

    3. Pre-collision brake assist control operation conditions:


      • Vehicle speed is approximately 30 km/h (19 mph) or more and approximately 80 km/h (50 mph) or less

      • Relative speed of vehicle ahead is approximately 30 km/h (19 mph) or more

      • VSC system is not disabled

    4. Pre-collision brake control operation conditions:


      • Vehicle speed is approximately 10 km/h (6 mph) or more and approximately 80 km/h (50 mph) or less

      • Relative speed of vehicle ahead is approximately 10 km/h (6 mph) or more

      • VSC system is not disabled

  10. PRECAUTION FOR PRE-COLLISION CITY SENSOR


    1. Conditions under which the system may operate even if there is no possibility of a collision.

      In the following situations the sensor may detect an object, causing the system to determine that there is a possibility of a frontal collision and operate.

      A002MDEE02
      Text in Illustration
      *A for RHD *B for LHD
      *a There are objects on the side of the road at the beginning of a curve (a guardrail, street light, billboard, etc.). *b Passing an oncoming vehicle on a curve.
      *c When passing an oncoming vehicle while making a left turn (for LHD) or right turn (for RHD). *d Passing through an area which contains an obstacle that covers the vehicle (such as a hanging curtain).
      *e There are metal objects, bumps and protrusions on the road (a metal plate covering road construction, a mesh drain cover, a manhole, etc.). *f Suddenly approaching a preceding vehicle.
      *g Approaching an electrical toll collection gate (reacts to bar). *h Crossing an overpass, traffic sign, signboard.
      *i The vehicle height drastically changes (nose-up, nose-down). *j When the sensor is misaligned due to a strong impact being applied to the sensor, etc.
      *k There is a billboard or sign at the top of an incline. *l There are metal objects at the bottom of a decline (a metal plate covering road construction, a mesh drain cover, a manhole, etc.).
      *m Snow, water, etc., is kicked up by the preceding vehicle. *n Passing through an area which contains heavy fog or smoke.
      *o When the vehicle is being parked in a place where there is a low hanging object at the height of the pre-collision city sensor *p Passing extremely close to the side of an obstacle (stopped vehicle, guardrail, etc.).

    2. Situations in which the pre-collision system may not function properly.

      The system may not function properly in the following situations:

      A002O9ME02
      Text in Illustration
      *a When driving on roads with sharp bends or uneven surfaces *b If a vehicle suddenly moves in front of the vehicle, such as at an intersection
      *c If a vehicle suddenly cuts in front of the vehicle *d If the vehicle is skidding
      *e When the front part of the vehicle is raised or lowered *f When the windshield is dirty or covered with raindrops, condensation, ice, snow, etc.
      *g When the sensor is misaligned due to a strong impact being applied to the sensor, etc. *h When a preceding vehicle is a poor reflector of laser (the rear part of the vehicle lowered, very dirty, etc.)
      *i When a very bright light, such as the sun or the headlights of oncoming traffic, shines directly into the pre-collision city sensor *j When driving in inclement weather such as heavy rain, fog, snow or a sand storm
      *k When the surrounding area is dark, such as while in a tunnel or during nighttime - -

  11. PRE-COLLISION SYSTEM AUTOMATIC CANCELLATION


    1. When a system malfunction is detected and the sensor cannot detect vehicles, system operation cancels automatically.

      Tech Tips

      When the system malfunctions or is temporarily disabled, the PCS warning light blinks.